Hypertension is the medical term for high blood pressure, a condition with many causes. Approximately 90% of people with high blood pressure have "essential" or "idiopathic" hypertension, for which the cause is poorly understood. The terms "hypertension" and "high blood pressure" as used here refer only to this most common form and not to high blood pressure either associated with pregnancy or clearly linked to a known cause, such as Cushing’s syndrome, pheochromocytoma, or kidney disease. Hypertension must always be evaluated by a healthcare professional. Extremely high blood pressure (malignant hypertension) or rapidly worsening blood pressure (accelerated hypertension) almost always requires treatment with conventional medicine. People with mild to moderate high blood pressure should work with a doctor before attempting to use the information contained here, as blood pressure requires monitoring and in some cases the use of blood pressure-lowering drugs.

As with conventional drugs, the use of natural substances sometimes controls blood pressure if taken consistently but does not lead to a cure for high blood pressure. Thus, someone whose blood pressure is successfully reduced by weight loss, avoidance of salt, and increased intake of fruits and vegetables would need to maintain these changes permanently in order to maintain control of blood pressure.

With the prevalence of salted processed and restaurant food, simply avoiding the salt shaker no longer leads to large decreases in salt intake for most people. Totally eliminating salt is more effective, but is also quite difficult to achieve. Moreover, whereas an overview of the research has reported "There is no evidence that sodium reduction as achieved in these trials presents any safety hazards,"⁵ reports of short-term paradoxical increases in blood pressure in response to salt restriction have occasionally appeared.⁶ Therefore, people wishing to use salt restriction to lower their blood pressure should consult with a doctor.

Vegetarian diets have been reported to significantly lower blood pressure.⁷ This occurs partly because fruits and vegetables contain potassium—a known blood pressure-lowering mineral.⁸ The best way to supplement potassium is with fruit, which contains more of the mineral than amounts found in potassium supplements. However, fruit contains so much potassium that people taking "potassium-sparing" diuretics (as some hypertensives do) can end up with too much potassium by eating several pieces of fruit per day. Therefore, people taking potassium sparing diuretics should consult the prescribing doctor before increasing fruit intake. The fiber provided by vegetarian diets may also help reduce high blood pressure.⁹ In the Dietary Approaches to Stop Hypertension (DASH) trial, increasing intake of fruits and vegetables (and therefore fiber) and reducing cholesterol and dairy fat led to large reductions in blood pressure (in medical terms, 11.4 systolic and 5.5 diastolic) in just eight weeks.¹⁰ Even though it did not employ a vegetarian diet itself, the outcome of the DASH trial supports the usefulness of vegetarian diets because diets employed by DASH researchers were related to what many vegetarians eat. The DASH trial also showed that blood pressure can be significantly reduced in hypertensive people (most dramatically in African Americans) with diet alone without weight loss or even restriction of salt.¹¹

Sugar has been reported to increase blood pressure in both animals¹² and humans.¹³ Though the real importance of this experimental effect remains somewhat unclear,¹⁴ some doctors recommend that people with high blood pressure cut back on their intake of sugar.

Shortly after consuming caffeine, blood pressure increases.¹⁵ In an analysis of 11 trials lasting almost two months on average, coffee drinking led to increased blood pressure, though these increases were typically small to moderate.¹⁶ Tea drinking has been reported to raise blood pressure immediately after consumption, but appears to not significantly elevate blood pressure over longer (24-hour) periods.¹⁷ Nonetheless, the effects of long-term avoidance of caffeine (from coffee, tea, chocolate, cola drinks, and some medications) on blood pressure remain unclear. A few reports have even claimed that long-term coffee drinkers have lower blood pressure than those who avoid coffee.¹⁸ On the basis of the two-month intervention trials, many doctors tell people with high blood pressure to avoid caffeine-containing food and drink despite the lack of clarity in published research.

Food allergy was reported to contribute to high blood pressure in a study of people who had migraine headaches.¹⁹ In that report, all 15 people who also had high blood pressure experienced a significant drop in blood pressure when put on a hypoallergenic diet. People suspecting food allergies should check with a doctor.

Exposure to lead and other heavy metals has also been linked to high blood pressure in some,²⁰ but not all, research.²¹ If other approaches to high blood pressure prove unsuccessful, it makes sense for people with hypertension to have their body’s burden of lead evaluated by a healthcare professional.

Many studies have found a relationship between alcohol consumption and blood pressure. A recent review of the research reported that above the equivalent of approximately three drinks per day, blood pressure increases in proportion to the amount of alcohol consumed.²³ Whether one or two drinks per day meaningfully increases blood pressure remains unclear.

Daily exercise can lower blood pressure significantly.²⁴ People over 40 years of age should consult with their doctor before starting an exercise regime. A 12-week program of Chinese T’ai Chi was reported to be almost as effective as aerobic exercise in lowering blood pressure in sedentary elderly people with high blood pressure.²⁵

Many people with high blood pressure are overweight. Weight loss can lower blood pressure significantly in those who are both overweight and hypertensive.²⁶ People with hypertension who are overweight should talk with a doctor about a weight loss program.

Nutritional supplements that may be helpful: Calcium supplementation—typically 800–1,500 mg per day—lowers blood pressure. However, while an analysis of 42 trials reported that calcium supplementation led to an average drop in blood pressure that was highly statistically significant, the decrease was not large enough to meaningfully improve health (in medical terms, a drop of 1.4 systolic over 0.8 diastolic pressure).²⁷ Results would likely be better were analysis limited only to studies of hypertensive people, because calcium has little if any effect on those with normal blood pressure. In the analysis of 42 trials, effects were seen both with dietary calcium and with use of calcium supplements. Although average decreases in blood pressure from calcium are clearly small, each person responds differently. Some evidence suggests that people with hypertension whose blood pressure is affected most by changes in salt intake respond best to calcium supplementation.²⁸ A 12-week trial of 1,000 mg per day of calcium accompanied by blood pressure monitoring is a reasonable way to assess efficacy in a given individual.

Some,²⁹ but not all,³⁰ studies show that magnesium supplements—typically 350–500 mg per day—lower blood pressure. Magnesium appears to be particularly effective in people who are taking potassium depleting diuretics.³¹ As so-called "potassium depleting" diuretics also deplete magnesium, the drop in blood pressure resulting from magnesium supplementation in people taking these drugs may result from overcoming a mild magnesium deficiency.

Vitamin C plays an important role in maintaining the health of arteries.³² A review of vitamin C research reported that most studies linked increased blood and dietary levels of the vitamin to reduced blood pressure.³³ However, these links might result from diets high in fruits and vegetables rather than from vitamin C itself. The same review reported that blood pressure was reduced in all four double-blind trials examining the effects of vitamin C, but the reduction was statistically significant in only two of the four, and in some cases reductions were quite modest. Nonetheless, some doctors recommend that people with elevated blood pressure supplement with 1,000 mg vitamin C per day.

Coenzyme Q10 (CoQ10) has been reported to affect blood vessels in a way that should cause a decrease in blood pressure.³⁴ Both uncontrolled^{35 36 37} and controlled trials have reported that CoQ10 significantly lowers blood pressure in people with hypertension.^{38 39} All trials used at least 50 mg of CoQ10 taken twice per day, and most trials lasted for at least ten weeks.

A deficiency of the amino acid taurine is thought by some researchers to play an important role in elevating blood pressure in people with hypertension.⁴¹ Limited taurine research has found that supplementation lowers blood pressure in animals⁴² and people (at 6 grams per day),⁴³ possibly by reducing levels of the hormone epinephrine (adrenaline).

The amino acid arginine is needed by the body to make nitric oxide, a substance that allows blood vessels to dilate, thus leading to reduced blood pressure. As a result, intravenous administration of arginine has reduced blood pressure in humans in some reports.⁴⁴ Most research has not used oral arginine, but in one such trial, the combination of arginine (2 grams taken three times per day) plus conventional drugs used to treat hypertension was significantly more effective than placebo alone in patients who previously did not respond to the same drugs taken without arginine.⁴⁵

Herbs that may be helpful: Garlic lowers blood pressure, according to a meta-analysis that included ten double-blind studies.⁴⁶ All of these trials administered garlic for at least four weeks, typically using 600–900 mg of garlic extract per day.

One non-randomized study on humans has shown that an extract of coleus called forskolin can reduce blood pressure and improve heart function in people with cardiomyopathy.⁴⁷ Forskolin was given by injection in this study; it is unknown if oral coleus extracts would have the same effect. Coleus extracts standardized to 18% forskolin are available, and 50–100 mg can be taken two to three times per day. Fluid extract can be taken in the amount of 2–4 ml three times per day. Most studies have used injected forskolin, so it is unclear if oral ingestion of coleus extracts will provide similar benefits in the amounts recommended above.

Uncontrolled studies carried out using oral mistletoe have found it can reduce the symptoms of high blood pressure, particularly headaches and dizziness.⁴⁸ It can be taken in the amount of 0.5 ml tincture three times per day.⁴⁹ Despite its reputation, one eminent medical herbalist insists that mistletoe has a small (if any) effect on actually lowering blood pressure.⁵⁰ European mistletoe has potential toxicity and can cause serious side effects if used incorrectly. It should not be taken except under the careful supervision of a physician highly trained in its use.

Indian snakeroot (Rauwolfia serpentina) contains powerful alkaloids, including reserpine, that affect blood pressure and heart function. Indian Snakeroot has been used traditionally to treat essential hypertension, especially when associated with stress and anxiety.⁵¹ Indian Snakeroot should be taken under the careful supervision of a physician trained in its use; it has potential toxicity and can cause serious side effects if used incorrectly.

It has been hypothesized that linden may relax muscles in arteries as well, thereby giving it a blood pressure-lowering effect.⁵² However, this remains speculative and therefore the amount to use is also not known at this time.

In animal studies one of the constituents of olive leaf, oleuropein (when given by injection or in intravenous form), has been shown to decrease blood pressure (e.g., systolic and diastolic) and dilate the coronary arteries surrounding the heart.⁵³ This ability to lower blood pressure may justify the traditional use of olive leaf in the treatment of mild to moderate hypertension.⁵⁴ However, human studies are needed to clearly establish olive leaf as a potential treatment for high blood pressure.

Animal studies suggest that the mushroom maitake may lower blood pressure.⁵⁵ However, this research is still preliminary and requires confirmation.

A double-blind study found that menopausal women had improved function of their arteries while taking red clover extract compared to placebo.⁵⁶ This could mean that menopausal women would have less trouble with high blood pressure or atherosclerosis, though more study is required to be certain.

Two controlled clinical studies have investigated the effects of reishi on high blood pressure in humans and both found it could lower it significantly compared to placebo or controls.^{57 58} The people with hypertension in the second study had previously not responded to medications, though these were continued during the study.

Chinese scullcap might be useful for hypertension. However, the research on this is generally of low quality.⁵⁹

Other integrative approaches that may be helpful: Anxiety in men (but not women) has been linked to eventual hypertension in a respected long-term study.⁶⁰ Several research groups have shown a relationship between job strain and high blood pressure in men.^{61 62 63} Some researchers have tied blood pressure specifically to suppressed aggression.⁶⁴

Although some kind of relationship between stress and high blood pressure appears to exist, the effects of treatment for stress remain controversial. A meta-analysis of twenty-six trials reported that reductions in blood pressure caused by biofeedback or meditation were no greater than those seen with placebo.⁶⁵ Though some stress management interventions have not been at all helpful in reducing blood pressure,^{66 67} the more promising trials have used combinations of yoga, biofeedback, and/or meditation.^{68 69 70} Despite the lack of consensus in published research, many doctors continue to recommend a variety of stress-reducing measures, sometimes custom tailoring them to the person seeking help.

Acupuncture may be helpful in the treatment of hypertension in some people. Preliminary laboratory studies in animals⁷¹ and humans^{72 73 74} suggest an effect of acupuncture on blood pressure. One uncontrolled study reported significant reductions in blood pressure as well as related benefits to heart function in hypertensive patients.⁷⁵ A small controlled study found that electrical stimulation of acupuncture points lowered blood pressure in people with hypertension,⁷⁶ though another, placebo-controlled trial with menopausal women demonstrated no effect of acupuncture on blood pressure.⁷⁷ A controlled trial of 62 patients with hypertension reported acupuncture treatment and nifedipine (an antihypertensive medication) were equally effective in reducing blood pressure.⁷⁸ These positive results are supported by other controlled^{79 80} and uncontrolled trials.⁸¹ An important question remaining to be answered is whether blood pressure will stay lowered if acupuncture treatments are not regularly given.

Auricular (ear) acupressure has been reported to be an effective treatment for hypertension.^{82 83} In a large controlled trial, auricular acupressure treatment was compared to traditional herbal medicines for the treatment of hypertension. The auricular acupressure had an efficacy rate of 56–87%,⁸⁴ but these results were not significantly different from the herbal medicine group, so a placebo effect cannot be ruled out. Another controlled trial found self-acupressure using small pellets taped to ear acupuncture points was as effective as blood pressure medications, and better than placebo pills. In this study, the effects of acupressure persisted for four weeks after treatment was stopped.⁸⁵

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